| 摘要 |
PURPOSE:To suppress the uneven quantity of light on a scanning plane by providing a hologram disc disposed with holograms having roughly uniform diffraction efficiency of the holograms themselves along roughly the specified circumference and a rotating and driving means for rotating and driving the same. CONSTITUTION:A hologram disc 1 is so arranged as to be rotated and driven arond the axial line X of rotation thereof by a driving means consisting of a motor 2. Plural plane holograms disposed at an equal interval are provided on the disc 1 along the circumference centering at said axis X. A filter 8 is inserted into the optical path from the holograms up to a photoreceptor 10, and the filter 8 has the light transmittance distribution as shown by a curve F. The inconvenience of a fluctuation in diffraction efficiency is eliminated and the uneven quantity of light on the scanning plane is suppressed. |
